Anti-constipation composition

ABSTRACT

An object of the present invention is to provide an anti-constipation composition containing a halogenated-bi-cyclic compound as an active ingredient in a ratio of bi-cyclic/mono-cyclic structure of at least 1:1. The halogenated-bi-cyclic compound is represented by Formula (I): 
                         
where X 1  and X 2  are preferably both fluorine atoms. The composition can be used to treat constipation without substantive side-effects, such as stomachache.

This is a request for a Divisional Application of prior application Ser.No. 10/443,046 filed May 22, 2003, now abandoned which is a divisionalof U.S. application Ser. No. 10/138,650 filed May 6, 2002, now U.S. Pat.No. 6,610,732, which is a divisional of U.S. application Ser. No.09/655,760 filed Sep. 5, 2000, now U.S. Pat. No. 6,414,016; thedisclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a novel therapeutic composition thatcontains halogenated bi-cyclic structures for treatment of constipationand use thereof.

BACKGROUND OF THE INVENTION

Prostaglandins (hereinafter referred to as PGs) is the name of the groupof fatty acids which possess various physiological activities andcontained in human and animal tissues and organs. PGs basically containthe prostanoic acid skeleton of the following formula:

and some synthetic products may contain the above skeleton with somemodification. PGs are classified into several types according to thestructure and substituents on the five-membered ring, for example,

Prostaglandins of the A series (PGAs);

Prostaglandins of the B series (PGBs);

Prostaglandins of the C series (PGCs);

Prostaglandins of the D series (PGDs);

Prostaglandins of the E series (PGEs);

Prostaglandins of the F series (PGFs);and the like. Further, they are classified into PG₁s containing a13,14-double bond; PG₂s containing, 5,6- and 13,14-double bonds; andPG₃s containing 5,6-, 13, 14- and 17,18-double bonds.

PGs are expressed as follows. In PGs, the carbons constituting anα-chain, an ω-chain and a five-membered ring are numbered according tothe basic skeleton as follows:

That is, in the basic skeleton, the constituent carbon atoms arenumbered in such a way that the carbon atom in the carboxyl group isC-1, and the α-chain contains C-2-C-7, the number increasing toward thering, the five-membered ring contains C-8-C-12, and the ω-chain containsC-13-C-20. When the carbons of α-chain are fewer, the numbers of thecarbon atoms ensuing C-2 should be properly shifted, and when more than7, the compound is named provided that carbon at the C-2 position hassubstituent instead of carboxyl group (at the C-1 position). When theω-chain contains fewer carbon atoms they should be numberedcorrespondingly smaller than 20, and when more than 8, the carbon atomsat the 21 position and thereafter should be regarded as a substituent.As configuration, it is considered according to that of the aboveessential skeleton unless otherwise described.

For example, PGD, PGE and PGF mean compounds having hydroxyl group atthe C-9 and/or C-11 positions. In the present invention, PGs alsoinclude those having other group instead of the hydroxyl group on theC-9 and/or C-11 positions, they being named as 9-dehydroxy-9-substitutedor 11-dehydroxy-11-substituted compounds.

In addition, PGs may include the isomers, such as bi-cyclic tautomers,optical isomers; geometrical isomers, or the like.

PGs are known to have various pharmacological and physiologicalactivities, for example, vasodilation, inducing of inflammation,platelet aggregation, stimulating uterine muscle, stimulating intestinalmuscle, anti-ulcer effect and the like. PGEs or PGFs are found topossess contraction of intestines caused by intestinal stimulation isgreat, while enteropooling effect is poor. Accordingly, it is impossibleto use PGEs or PGFs as cathartics because of side effects such asstomachache caused by the intestinal contraction.

On the other hand, PGs having a 13,14-single bond and a C-15constituting carbonyl group, and those having a 13,14-double bond and aC-15 constituting carbonyl group are found to exist in human or animalmetabolites. These 13,14-dihydro-15-keto-prostaglandins and15-keto-prostaglandins (hereinafter referred to as 15-keto-PGs) areknown to be naturally produced metabolites by enzymatic metabolism ofthe corresponding PGs in vivo. These 15-keto-PGs have been reported tohardly exhibit various physiological activities that PGs possess and bepharmacologically and physiologically inactive metabolites [see, ActaPhysiologica Scandinavica, 66, p. 509-(1966)].

U.S. Pat. No. 5,317,032 to Ueno et al. describes prostaglandincathartics, including the existence of bi-cyclic tautomers. However, thepronounced activity as anti-constipation treatment and prevention agentsof the bi-cyclic tautomers has not been heretofore known.

While estimating the pharmacological activities of the analogues of15-keto-PGs, however, the present inventors have found that thecorresponding bi-cyclic compounds, i.e., the bi-cyclic tautomers,substituted by one or more halogen atoms can be employed in small dosesfor relieving constipation. At the C-16 position, especially, fluorineatoms, can be employed in small doses for relieving constipation. Wheredesired, larger doses to cause strong cathartic effect can be employed,although the primary purpose of the present invention is to restore anormal number of bowel movements (3 to 7 per week).

SUMMARY OF THE INVENTION

An object of the present invention is to provide a composition fortreatment of constipation comprising bi-cyclic-halogenated compoundswithout substantive side effects such as stomachache caused byintestinal contraction. Accordingly, the bi-cyclic-halogenated compoundsof the present invention may be used not only for treatment of chronicor intermittent constipation, but also for treatment or prevention ofconstipation (as well as to effect loose bowels when desired) in thepatients suffering from constipation associated with, for example, inhernia or cardiovascular system disease, in order not to strain atstool, or suffering from proctogenic diseases. Moreover, they may beused to produce normal bowel movements for washing out harmfulsubstances from intestine in case of drug or food poisoning.Additionally, the bi-cyclic halogenated compounds may be used as a bowelcleansing agent used for preparation of the bowel prior to preventative,diagnostic or surgical procedures.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an anti-constipation composition(prevention and/or treatment of constipation)containingbi-cyclic-halogenated compounds as active ingredients.

Cathartics work by the combination of one or more of the four mechanismsshown below, thereby increasing water content of feces and promotingtransfer of the content in the intestines:

(i) Water and electrolytes may be kept in intestines owing to thehydrophilicity or osmotic pressure of the drug, thereby theintraintestinal content increased in volume which indirectly results infaster transfer thereof.

(ii) The drug may work on the intestinal mucosa to reduce total amountof normal absorption of electrolytes and water and increase the amountof water, indirectly resulting in faster transfer of the intraintestinalcontent.

(iii) The drug may work on the intestinal mucosa to increase totalamount of normal secretion of electrolytes and water and increase theamount of water, directly and/or indirectly resulting in faster transferof the intraintestinal content.

(iv) The drug firstly works on intestinal movement to fasten transfer,indirectly resulting in reduced net absorption of water and electrolytesbecause the time for them to be absorbed is reduced.

The enteropooling test employed in the present invention is intended toinvestigate mainly on the action (ii) and/or (iii), which assesses theeffect of the drug on the intraintestinal water pool by measuring thevolume of the intraintestinal content. The bi-cyclic-halogenatedcompounds of the present invention may show extremely greatenteropooling effect. However, they hardly or slightly cause contractionof intestines which is one of indexes for assessment of the action (iv).Accordingly, the bi-cyclic-halogenated compounds of the presentinvention are considered to alleviate constipation by mainly acting onintestinal mucosa directly or indirectly to affect transfer ofelectrolytes and water from intestinal walls into blood vessels and/orfrom blood vessels into intestines, resulting in reduced waterabsorption and/or in increased water secretion through the intestines,increased intraintestinal water pool and promoted transfer of theintraintestinal content.

A preferred compound used in the present invention is represented byformula (I):

where V₁ and V₂ are carbon or oxygen atoms;

W₁ and W₂ are

R₃ and R₄ are both hydrogen atoms or one of them is OH;

X₁ and X₂ are hydrogen, lower alkyl or halogen atom, and at least one ofthese is a halogen atom;

Z is a carbon, oxygen, sulfur or nitrogen atom;

R₂ is a hydrogen atom or lower alkyl;

Y is a saturated or unsaturated C₂₋₁₀ hydrocarbon chain which isunsubstituted or substituted by oxo, halogen, an alkyl group, hydroxylor aryl;

A is —CH₂OH, —COCH₂OH, —COOH or its functional derivative; and

R₁ is a saturated or unsaturated, lower hydrocarbon forming astraight-chain, a branched-chain or a ring, which is unsubstituted orsubstituted by halogen, oxo, hydroxy, lower alkoxy, lower alkanoyloxy,lower cycloalkyl, lower cycloalkyloxy, aryl, or aryloxy. Preferably R₁is not substituted. Where a substituent is present, care must beexercised to avoid possible steric hinderance in formation of thebi-cyclic compound from or in association with the correspondingmono-cyclic PGs.

The steric configuration of C-15 can be R, S, or a mixture thereof.

The bond between C-13 and C-14 position can be a single or double bond.

In the above formula, the term “unsaturated” is intended to include atleast one or more double bonds and/or triple bonds that are isolatedly,separately, or serially present between the carbon atoms of the mainand/or side chains. An unsaturated bond between two serial positions isrepresented by denoting the lower number of the two positions, and anunsaturated bond between two distal positions is represented by denotingboth of the positions. Preferred unsaturated bonds are a double atposition 2 and a double or triple bond at position 5.

The term “lower” is intended to include a group having 1 to 8 carbonatoms, unless otherwise specified.

The term “ring” includes lower cycloalkyl, lower cycloalkoxy, aryl oraryloxy.

The term “halogen” includes fluorine, chlorine, bromine, or iodine atom.Particularly preferable is a fluorine atom.

The term “lower alkoxy” refers to a group of lower alkyl-O—, whereinlower alkyl is a straight or branched chain saturated hydrocarbon groupcontaining 1 to 6 carbon atoms and includes, for example, methyl, ethyl,propyl, isopropyl, buyl, isobutyl, t-butyl, pentyl and hexyl.

The term “hydroxy(lower)alkyl” refers to a lower alkyl as defined abovewhich is substituted with at least one hydroxy group such ashydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl and1-methyl-1-hydroxyethyl.

The term “lower alkanoyloxy” refers to a group represented by theformula RCO—O—, wherein RCO— is an acyl group formed by oxidation of alower alkyl group as defined above, such as acetyl.

The term “lower cycloalkyl” refers to a cyclic group formed bycyclization of a lower alkyl group as defined above but contains threeor more carbon atoms, and includes, for example, cyclopropyl,cyclobutyl, cyclopentyl and cyclohexyl.

The term “lower cycloalkyloxy” refers to the group oflower-cycloalkyl-O—, wherein lower cycloalkyl is as defined above.

The term “aryl” may include unsubstituted or substituted aromaticcarbocyclic or heterocyclic groups (preferably mono-cyclic groups), forexample, phenyl, naphthyl, tolyl, xylyl, furyl, thienyl, pyrrolyl,oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl,furzanyl, pyranyl, pyridyl, pyridazyl, pyrimidryl, pyrazyl,pyrrolidinyl, imidazolidinyl, pyrazolidinyl, piperidino, piperazinyl,morpholono, indolyl, benzothienyl, quinolyl, isoquinolyl, puryl,quinazolinyl, carbazolyl, acridinyl, phenathridinyl, benzimidazolyl,benzimidazolonyl, benzothiazolyl and phenothiazinyl. Examples ofsubstituents are halogen atom and halo(lower)alkyl, wherein halogen atomand lower alkyl are as defined above.

The term “aryloxy” refers to a group represented by the formula Ar—O,wherein Ar is aryl as defined above.

The bi-cyclic-16-halogen compounds used in the present invention may besalts or those with an esterified carboxyl group or etherified group.Such salts include pharmaceutically acceptable salts, for example, thoseof alkali metals such as sodium, potassium; those of alkaline earthmetals such as calcium, magnesium; those of physiologically acceptableammonium salts such as ammonia, methylamine, dimethylamine,cyclopentylamine, cyclohexylamine, benzylamine, piperidine,ethylenediamine, monoethanolamine, diethanolamine, triethanolamine,monomethylmonoethanolamine, trometamine, lysine, procaine, caffeine,arginine, tetralkylammonium salt and the like. These salts may beprepared by a conventional process, for example, from the correspondingacid and base or by salt interchange.

Such esters and ethers include, for example, straight or branched alkylesters and ethers which may contain one or more unsaturated bonds suchas methyl, ethyl, propyl, butyl, isopropyl, isobutyl, t-butyl, pentyl,2-ethylhexyl; those having an alicyclic group such as a cyclopropyl,cyclopentyl or cyclohexyl group; those containing an aromatic group suchas a benzyl or phenyl group (wherein the aromatic group may contain oneor more substituents); a lower alkenyl such as ethynyl and propynyl,hydroxyalkyl or alkoxyalkyl such as hydroxyethyl, hydroxyisopropyl,polyhydroxyethyl, polyhydroxyisopropyl, methoxyethyl, ethoxyethyl ormethoxyisopropyl ester or ether; optionally substituted aryls such asphenyl, tosyl, t-butylphenyl, salicyl, 3,4-di-methoxyphenyl andbenzamidophenyl; alkylsilyls such as a trimethylsilyl or triethylsilyl;or a tetrahydropyranyl ester or ether.

Preferred esters and ethers include, for example, straight-chain orbranched lower alkyl such as methyl, ethyl, propyl, n-butyl, isopropylor t-butyl; a benzyl; or hydroxyalkyl such as a hydroxyethyl orhydroxyisopropyl.

Preferred A is —COOH or its pharmaceutically acceptable salt or ester.

Preferred X₁ and X₂ are both being halogen atoms, and more preferably,fluorine atoms.

Preferred W₁ is ═O.

Preferred W₂ is where R₃ and R₄ are both hydrogen atoms.

Preferred Z is an oxygen atom.

Preferred Y is an unsubstituted saturated or unsaturated hydrocarbonchain having 6-8 carbon atoms.

Preferred R₁ is an unsubstituted saturated or unsaturated hydrocarbonchain having 4-8 carbon atoms.

R₂ is preferably a hydrogen atom.

The composition of the present invention may include the isomers of theabove compounds. Examples of such isomers include mono-cyclic tautomershaving a keto group at the C-15 position and halogen at the C-16position; optical isomers; geometrical isomers and the like.

The tautomerism between the oxygen atom at the C-11 position and theketo group at the C-15 position, shown above, is especially significantin the case of compounds having a 13,14-single bond and two fluorineatoms at the C-16 position.

It has been discovered that in the absence of water, compoundsrepresented by Formula (I) exist predominantly in the form of thebi-cyclic compound. In aqueous media, it is believed that hydrogenbonding occurs between, for example, the ketone position at the C-15position, thereby hindering bi-cyclic ring formation. In addition, it isbelieved that the halogen atom(s) at the C-16 position promote bi-cyclicring formation. The mono-cyclic/bi-cyclic structures, for example, maybe present in a ratio of 1:6 in D₂O; 1:10 in CD₃OD-D₂O and 4:96 inCDCl₃. Accordingly, a preferable embodiment of the present invention isthe composition in which the bi-cyclic form is present in ratio of bi-cyclic/mono-cyclic of least 1:1, and preferably 20:1, or even greaterto substantially all bi-cyclic compound; 100% bi-cyclic compound iswithin this invention.

The above described bi-cyclic-16-halogen compound may prepared accordingto the general process set forth below:

Preparation of Isopropyl7-[(1S,3S,6S,7R)-3-heptyl-3-hydroxy-bicyclo[4.3.0]nonane-8-one-7-yl]hept-5-enoateand Isopropyl7-[1S,3R,6S,7R)-3-heptyl-3-hydroxy-bicyclo[4.3.0]nonane-8-one-7-yl]hept-5-enoate 1.Preparation of Isopropyl(Z)-7-[1R,2R,3R,5S)-2-(3,3-ethylenedioxydecyl)-5-hydroxy-3-(p-toluensulfonyl)cyclopentyl]hept-5-enoate(2)

To a mixture of pyridine (0.77 g) andisopropyl(Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-(3,3-ethylenedioxydecyl)cyclopentyl]hept-5-enoate(1) (4.05 g) in dichloromethane, a solution of tosyl chloride (1.86 g)in dichloromethane was added at 0° C., and stirred for 2 days at thetemperature. During the reaction, each tosyl chloride (5.58 g) andpyridine (2.31 g) was added in three portions. After the usual work-up,the crude product was chromatographed on silica gel to give isopropyl(Z)-7-[(1R,2R,3R,5S)-2-(3,3-ethylenedioxydecyl)-5-hydroxy-3-(p-toluenesulfoxy)cyclopentyl]hept-5-enoate(2). Yield 3.45 g, 64.1%.

2. Preparation of Isopropyl(Z)-7-[(1R,2S)-2-(3,3-ethylenedioxydecyl)-5-oxocyclopent-3-enyl]hept-5-enoate(3)

Isopropyl (Z)-[1R,2R,3R,5S)-2-(3,3-ethylenedioxydecyl)-5-hydroxy-3-(p-toluenesulfoxy)cyclopentyl]hept-5-enoate(2) (1.72 g) was oxidized in acetone at −40° C. to −20° C. with Jonesreagent for 4 hours. After the usual work-up, the crude product waspassed through silica gel pad with n-hexane/ethyl acetate (3.5/1). Theproduct was further chromatographed on silica gel (n-hexane/ethylacetate=4/1). Isopropyl(Z)-7-[(1R,2S)-2-(3,3-ethylenedioxydecyl)-5-oxo-cyclopent-3-enyl]hept-5-enoate(3) was obtained. Yield 0.81 g, 64.6%.

3. Preparation ofIsopropyl-7-[(1R,2S,3R)-2-(3,3-ethylenedioxydecyl)-3-hydroxymethyl-5-oxocyclopentyl]hept-5-enoate(4)

Isopropyl(Z)-7-[(1R,2S)-2-(3,3-ethylenedioxydecyl)-5-oxo-cyclopent-3-enyl]hept-5-enoate(3) (0.81 g) and benzophenone were dissolved in methanol. Under argonatmosphere, the solution was irradiated with 300-W high-pressure mercurylamp for 4 hours and 40 minutes. After evaporation of the solvent, thecrude product was chromatographed on silica gel (n-hexane/ethylacetate=3/2) to give isopropyl-7-[(1R,2S,3R)-2-(3,3-ethylenedioxydecyl)-3-hydroxymethyl-5-oxocyclopentyl]hept-5-enoate(4). Yield 0.41 g, 47%.

4. Preparation ofIsopropyl-7-[1R,2S,3R)-2-(3,3-ethylenedioxydecyl)-5-oxo-3-(p-toluenesulfoxymethyl)cyclopentyl]hept-5-enoate(5)

Isopropyl-(1R,2S,3R)-2-(3,3-ethylenedioxydecyl)-3-hydroxymethyl-5-oxocyclopentyl]hept-5-enoate(4) (0.21 g) and pyridine (0.07 g) were dissolved in dichloromethane. Tothis solution, tosyl chloride (0.17 g) was added at 0° C., and themixture was stirred for 72 hours. After the usual work-up, the crudeproduct was chromatographed on silica gel to give isopropyl7-(1R,2S,3R)-2-(3,3-ethylenedioxydecyl)-5-oxo-3-(p-toluenesulfoxy)methylcyclopentyl]hept-5-enoate(5). Yield 0.25 g, 89%.

5. Preparation ofIsopropyl-7-[(1R,2R,3R)-2-(3,3-ethylenedioxydecyl)-3-iodemethyl-5-oxocyclopentyl]hept-5-enoate(6)

Isopropyl7-(1R,2S,3R)-2-(3,3-ethylenedioxydecyl)-5-oxo-3-(p-toluenesulfoxy)methylcyclopentyl]hept-5-enoate(5) (0.25 g) was dissolved in acetone, and sodium iodide (0.12 g) wasadded. The mixture was refluxed for 3 hours. Sodium iodide (0.097 g) wasadded to the mixture, and the mixture was refluxed for additional 80minutes. After the usual work-up, the crude product was chromatographedon silica gel (n-hexane/ethyl acetate=5/1) to give isopropyl7-(1R,2R,3R)-2-(3,3-ethylenedioxydecyl)-3-iodemethyl-5-oxocyclopentyl]hept-5-enoate(6). Yield 0.16 g, 68%.

6. Preparation of Isopropyl7-(1R,2R,3R)-3-iodemethyl-5-oxo-2-(3-oxodecyl)cyclopentyl]hept-5-enoate(7)

Isopropyl 7-(1R,2R,3R)-2-(3,3-ethylenedioxydecyl)-3-iodemethyl-5-oxocyclopentyl]hept-5-enoate(6) (0.16 g) was dissolved in a mixed solvent of aceticacid/water/tetrahydrofuran (3/1/1). The mixture was stirred for 20 hoursat room temperature and for 2.5 hours at 50° C. After evaporation of thesolvent, the obtained residue was chromatographed on silica gel(n-hexane/ethyl acetate=1/1) to give isopropyl7-(1R,2R,3R)-3-iodemethyl-5-oxo-2-(3-oxodecyl)cyclopentyl]hept-5-enoate(7). Yield. 0.13 g; 86%.

7. Preparation of Isopropyl7-(1S,3S,6S,7R)-3-heptyl-3-hydroxy-bicyclo[4.3.0]nonane-8-one-7-yl]hept-5-enoate(8a) and Isopropyl7-(1S,3R,6S,7R)-3-heptyl-3-hydroxy-bicyclo[4.3.0]nonane-8-one-7-yl]hept-5-enoate(8b)

Isopropyl7-(1R,2R,3R)-3-iodemethyl-2-(3-oxodecyl)-5-oxocyclopentyl]hept-5-enoate(7) (0.0574 g) and zirconocene dichloride were dissolved intetrahydrofuran. The mixture was sonicated under argon stream to purgethe air out from the mixture. To the mixture samarium iodide intetrahydrofuran (0.1 M, 2.1 mL) was added dropwise. The mixture wasstirred for 30 minutes at room temperature, and then hydrochloric acid(0.1M, 1 mL) was added. After the usual work-up, the crude product waschromatographed on silica gel (n-hexane/ethyl acetate=5/1). Two bicyclicproducts, more polar (8a) and its epimer, less polar (8b) and startingmaterial (7) were obtained as follows:

Isopropyl7-(1S,3S,6S,7R)-3-heptyl-3-hydroxy-bicyclo[4.3.0]nonane-8-one-7-yl]hept-5-enoate(8a) and Isopropyl7-(1S,3R,6S,7R)-3-heptyl-3-hydroxy-bicyclo[4.3.0]nonane-8-one-7-yl]hept-5-enoate(8b): Yield 8(a) 5.1 mg, Yield 8(b) 7.2 mg, Recovery of startingmaterial (7) 26.7 mg.

A theoretical synthesis for a compound represented by Formula (I) whereZ is a sulfur atom and W₁ is an —OH group is set forth below.

A theoretical synthesis for a compound represented by Formula (I) whereZ is a sulfur atom and W₁ is a keto is set forth below:

A theoretical synthesis for a compound represented by Formula (I) whereZ is a sulfur atom, W₁ is a keto and X₁ and X₂ are fluorine atoms is setforth below:

A theoretical synthesis for a compound represented by Formula (I) whereZ is a nitrogen atom is set forth below:

Another theoretical synthesis of a compound represented by Formula (I)where Z is a nitrogen atom is set forth below:

The preparations in the present invention are not construed to belimited to them, and suitable means for protection, oxidation, reductionand the like may be employed.

In the bi-cyclic-16-halogen compounds used in the present invention,enteropooling activity is remarkably enhanced when substituted by twohalogen atoms, especially fluorine atoms, at the C-16 positionindependently of the structure and substituents of the five-memberedring or the existence of the double bonds or other substituents.Particularly preferable bi-cyclic-16-halogen compounds are thosetautomers formed from mono-cyclic compounds having a ketone at the C-9position and a hydroxyl group at the C-11 position in the five memberedring. Another preferable group is a bi-cyclic-16-halogen compoundcontaining a 5,6-single bond, 5,6-double bond or those having the carbonnumber 20-22 where R₁ contains 4 to 6 carbon atoms preferably in astraight chain.

An example of a mono-cyclic/bi-cyclic-16-halogen compound containing a5,6-double bond are set forth below:

Another embodiment of the present invention comprises the composition ofthe present invention and a medium chain fatty acid triglyceride. Thetriglyceride may be a saturated or unsaturated fatty acid having 6-14carbon atoms that may have a branched chain. A preferred fatty acid is astraight chain saturated fatty acid, for example, caproic acid, caprylicacid, capric acid, lauric acid and myristic acid. 2 or more medium chainfatty acid triglycerides may be used as a mixture.

The composition of the present invention may be dissolved or admixed inthe medium chain fatty acid triglyceride. The amount of the medium chainfatty acid triglyceride is not limited. However, generally, 1-1,000,000parts by weight of the medium chain fatty acid triglyceride based on onepart by weight of the bi-cyclic structure may be used. Preferably,5-500,000 parts by weight, and more preferably 10-200,000 parts byweight.

Examples of the medium chain fatty acid triglyceride used in the presentinvention include a triglyceride of a saturated or unsaturated fattyacid having 6-14 carbon atoms which may have a branched chain. Preferredfatty acid is a straight chain saturated fatty acid for example caproicacid (C6), caprylic acid (C8), capric acid (C10), lauric acid (C12) andmyristic acid (C14). In addition, 2 or more medium chain fatty acidtriglycerides may be used.

Even more non-polar solvents, such as commercially available Miglyol canbe employed to increase the bi-cyclic/mono-cyclic ratio.

To exemplify formulation of an embodiment of the present invention andto illustrate potential effect of steric hinderance, an Example is setforth.

EXAMPLE

The following compounds 1 and 2 were dissolved in a medium chain fattyacid triglyceride (MCT=mixture of caprylic acid triglyceride and capricacid triglyceride in a ratio of 85:15) in an amount shown in the tablebelow.

Each of the solutions was placed in a container made of hard glass andstored at 40° C. The time-course content of compound 1 and 2 in thesolutions were determined by HPLC method. At the same time, each ofcompounds 1 and 2 was placed solely (without being dissolved in thesolvent) in the container as above, and stored at 40° C. to providecontrol study.

(1) In the absence of the solvent, the content of the compounds wasdetermined as follows by the HPLC method.

Stored compounds 1 and 2, and standard compounds 1 and 2 were weighedprecisely around 0.025 g each, and exactly 5 mL aliquots of internalstandard solution were added to the respectively weighed compounds. Testand standard preparations were obtained by adding acetonitrile (liquidchromatograph grade) to give the precise total amount of 10 mL each.Each 10 μL of the test and standard preparations were loaded on liquidchromatograph and determined the content of the compound by internalstandard method with one point calibration curve.

${{content}\mspace{14mu}(\%)} = {\frac{Q_{T}}{Q_{S}} \times W_{S} \times \frac{100}{W_{T}}}$

W_(X): The amount of the compound in the standard preparation (mg)

W_(T): The amount of compound 1 and 2 in the test preparation.

Q_(S): Peak area ratio of the compound in the standard preparation tothe internal standard.

Q_(T): Peak area ratio of the compound in the test preparation to theinternal standard.

Measurement Conditions:

Detector: Ultraviolet absorption spectrophotometer (wavelength 294 nm)

Column: A stainless tube having about 5 mm of internal diameter andabout 25 cm of length, packed with 5 μm octadecylsilyl silica gel forliquid chromatograph

Column temperature: Stable around 35° C.

Mobile phase: Mixed solution of acetonitrile (liquid chromatographgrade)/aqueous sodium acetate (0.01 mol/L)/glacial acetic acid(800:200:1)

(2) In the presence of the solvent, the content of the compound wasdetermined as follows by HPLC method.

Based on the value expressed in the above table, an amount of thesolution corresponding to 36 μg of compounds 1 and 2 was weighedprecisely. Precisely 1.0 mL of an internal standard solution was added,and then ethyl acetate, (liquid chromatograph grade) was added to give atotal amount of 10 mL each. Each 0.1 mL of the solution was vacuumconcentrated to dryness to give the test preparation.

Each 18 mg of the standard compounds was weighed precisely and admixedwith ethyl acetate (liquid chromatograph grade) to give the total amountof exactly 50 mL each. 1.0 mL of the solution and 10.0 mL of theinternal standard solution were measured precisely and admixed withethyl acetate (liquid chromatograph grade) to give a total of 100 mLeach. Each 0.1 mL of the solution was vacuum concentrated to dryness togive the standard preparation.

To the test and standard preparations, 0.1 mL of fluorescent labelingreagent and 0.85 mL of fluorescent labeling catalyst were added,respectively, and the mixture was stirred and reacted at roomtemperature for more than 30 minutes. 0.05 mL aliquots of acetonitrile(liquid chromatograph grade) containing 2% acetic acid were added to thereaction mixtures, respectively, stirred, and then allowed to stand formore than 30 minutes to provide test and standard solutions.

Each 10 μL of the test and standard solution was loaded on liquidchromatograph and determined the content of the respective compounds byinternal standard method with one point calibration curve.

${{content}\mspace{14mu}(\%)} = {\frac{Q_{T}}{Q_{S}} \times W_{S} \times \frac{100}{18}}$

W_(X): The amount of the compound in the standard preparation (mg)

Q_(S): Peak area ratio of the compound in the standard preparation tothe internal standard.

Q_(T): Peak area ratio of the compound in the test preparation to theinternal standard.

Measurement Conditions:

Detector: Fluorescent spectrometer (excitation wavelength 259 nm;fluorescent wavelength 394 nm)

Column: A stainless tube having about 5 mm of internal diameter andabout 25 cm of length, packed with 5 μm octadecylsilyl silica gel forliquid chromatograph

Column temperature: Stable at around 35° C.

Mobile phase: Mixed solution of acetonitrile (liquid chromatographgrade)/methanol (liquid chromatograph grade)/aqueous ammonium acetate(0.05 mol/L) (4:11:5)

initial 6 days 7 days 14 days 28 days 38 days 90 days 191 days compound1 crystal 100 97.2 94.1 87.4 MCT¹ 100 101.4 102.1 100.9 compound 2crystal 100 84.5 75.0 53.4 MCT² 100 99.6 98.9 99.6 ¹compound 1/solvent:0.36 mg/g ²compound 2/solvent: 0.12 mg/g

The composition of the present invention causes extremely greatenteropooling effect, inhibiting absorption of water in intestines.Further, the present compounds have no or greatly reduced, if any,intestinal contraction effect which PGEs or PGFs may possess. Therefore,the present composition treats constipation without malaise in bellyowing to the intestinal contraction, such as bellyache. In addition, thepresent compound allows constipation to subside effecting normal bowlconditions. Moreover, it requires little time to recover from diarrheasymptoms if caused by the present compounds which possess greatpromotion effect of intraintestinal transportation. Therefore, they areeven very useful as cathartics.

The composition of the present invention can be used as constipationtreatment and prevention remedies for animals and humans, and, ingeneral, used for systemic or local applications by oral administration,or as suppository, enema and the like. Sometimes, they may be applied asintravenous or subcutaneous injection. The dosage varies depending onanimals, humans, age, weight, conditions, therapeutic effect,administration route, treatment time and the like. Preferably, it is0.001-1,000 μg/kg, and more preferably 0.01 to 100 μg/kg.

The solid composition for oral administration of the present inventionincludes tablets, preparations, granules and the like. In such a solidcomposition, one or more active ingredients may be mixed with at leastone inactive diluent, for example, lactose, mannitol, glucose,hydroxypropyl cellulose, microcrystalline cellulose, starch, polyvinylpyrrolidone, magnesium aluminate metasilicate and the like. According tothe usual work-up, the composition may contain additives other thaninactive diluent, for example, lubricant such as magnesium stearate;disintegrant such as fibrous calcium gluconate; stabilizer such ascyclodextrin, for example, α,β- or γ-cyclodextrin; etherifiedcyclodextrin such as dimethyl-α-, dimethyl-β-, trimethyl-β- orhydroxypropyl-β-cyclodextrin; branched cyclodextrin such as glucosyl-,maltosyl-cyclodextrin; formylated cyclodextrin, cyclodextrin containingsulfur; phospholipid and the like. When the above cyclodextrins areused, inclusion compound with cydodextrins may be sometimes formed toenhance stability. Alternatively, phospolipid may be sometimes used toform liposome, resulting in enhanced stability.

Tablets or pills may be coated with film soluble in the stomach orintestine such as sugar, gelatin, hydroxypropyl cellulose,hydroxypropylmethyl cellulose phthalate as needed. Further, they may beformed as capsules with absorbable substances such as gelatin.

A liquid composition for oral administration may containpharmaceutically acceptable emulsion, solution, suspension, syrup, elixias well as generally used inactive diluent. Such composition maycontain, in addition to the inactive diluent, adjuvants such assuspensioning agents, sweetening agents, flavoring agents,preservatives, solubilizers, anti-oxidants and the like. The details ofthe additives may be selected from those described in any generaltextbooks in the pharmaceutical field. Such liquid compositions may bedirectly enclosed in soft capsules. However, the selection of a diluentother than those mentioned above, which the bi-cyclic/mono-cycliccompound may be dissolved or admixed in, must carefully be selected soas not to affect the bi-cyclic/mono-cyclic ratio.

Solutions for parenteral administration, for example, suppository, enemaand the like according to the present invention include steril, aqueousor non-aqueous solution, suspension, emulsion and the like. The aqueoussolution and suspension includes, for example, distilled water,physiological saline and Ringer's solution.

The non-aqueous solution and suspension include, for example, propyleneglycol, polyethylene glycol, fatty acid triglyceride, vegetable oil suchas olive oil, alcohols such as ethanol, polysorbate and the like. Suchcomposition may contain adjuvants such as preservatives, wetting agent,emulsifier, dispersant, anti-oxidants and the like.

The present invention will be illustrated in the following examples.Which are illustrated by way of example only and not intended to limitthe scope of the present invention.

Correlation of Mono-Cyclic/Bi-Cyclic Structure and Biological Activity

To exemplify the effect of halogenated-bi-cyclic compounds with halogenatoms at the C-16 position in the composition of the present invention,the following Examples were prepared and tested.

Example 1

The biological activity of compositions due to the ratios ofmono-cyclic/bi-cyclic structures when Z of general formula (I) is anoxygen atom, and a ketone is present at the C-9 position of the presentinvention can be seen from the following examples. The number offluorine atoms at the C-16 position and the ratio ofmono-cyclic/bi-cyclic structures are shown in Table 1.

Enteropooling tests and diarrhea tests were conducted. The results areset forth in Table 1. The dose that raise the intraintestinal content by50% was referred to as ED₅₀.

TABLE 1 Comparative Example A Example B Example A Number of F atoms 2 10 at C-16 position Ratio of mono- 4:96 1:1 No signal cyclic/bi-cyclicderived from structure* bi-cyclic structure was detected. Enteropooling0.6 μg/kg 2 μg/kg 320 μg/kg activity, ED₅₀ Diarrhea in mice +: at 3mg/kg −: at 10 (PO¹) mg/kg (PO) +: at 0.3 mg/kg ±: at 0.3 −: at 1 (SC²)mg/kg (SC) mg/kg (SC) *Determined by NMR measurement in CDCl₃ solution.¹PO is by mouth (oral administration) ²SC is subcutaneous administration

Example 2

The biological activity of the composition due to the ratios ofmono-cyclic/bi-cyclic structures when Z in Formula (I) is an oxygen, aketone is present at the C-9 position, and there is a double bondbetween the 5,6-carbons is shown below.

Enteropooling tests and diarrhea tests were conducted. The results areset forth below in Table 2. The dose that raise the intraintestinalcontent by 50% was referred to as ED₅₀.

TABLE 2 Comparative Example C Example D Example C Number of F atoms 2 10 at C-16 position Ratio of mono- 4:96 1:1 no signal derived fromcyclic/bi-cyclic bi-cyclic structure was structure* detected.Enteropooling 0.3 μg/kg 3 μg/kg 220 μg/kg activity, ED₅₀ Diarrhea inmice +: at 1 −: at 1 −: at 10 mg/kg (PO) mg/kg (PO)¹ mg/kg (PO) +: at 5mg/kg (PO) *Determined by NMR measurement in CDCl₃ solution. ¹PO is bymouth (oral administration)Effect of the Present Invention Dissolved in Medium Chain Fatty AcidTriglyceride on Bowel Movement After Single Oral Administration toHealthy Male Volunteers

3 to 9 healthy male volunteers were treated with a compositioncontaining the following mono-cyclic/bi-cyclic structures (in CDCl₃) ina ratio of 4:96.

The test substance (R₁ and R₂ are F atoms) was dissolved in Panacet 800(medium chain fatty acid triglyceride manufactured by Nippon Oil & Fatco., Ltd., Amagasaki, Japan) and filled in a capsule (each capsulecontains 200 L of the mixture). Each subject was administered onecapsule with 100 mL of water.

Table 3 shows the number of subjects who experienced loose stool ordiarrhea.

TABLE 3 Number of Subjects Dose Normal Loose or Diarrhea  5 μg 1/3 2/310 μg 5/7 2/7 20 μg 1/3 2/3 30 μg 2/9 7/9

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

1. A method for relieving constipation in a constipated patient orcleansing the bowel of a patient, comprising administering to saidpatient a therapeutically effective amount of a composition comprisingthe bi-cyclic and mono-cyclic tautomers of13,14-dihydro-15-keto-16,16-difluoro-prostaglandin E1, wherein the ratioof the bi-cyclic to mono-cyclic tautomer is at least 1:1.
 2. The methodaccording to claim 1, wherein the ratio of bi-cyclic to mono-cyclictautomer is at least 20:1.
 3. The method according to claim 1, whereinthe ratio of bi-cyclic to mono-cyclic tautomer is about 96:4.
 4. Amethod for relieving constipation in a constipated patient or cleansingthe bowel of a patient, comprising administering to said patient atherapeutically effective amount of a composition comprising thebi-cyclic and mono-cyclic tautomers of13,14-dihydro-15-keto-16,16-difluoro-prostaglandin E1,and at least onemedium fatty acid triglyceride, wherein the ratio of the bi-cyclic tomono-cyclic tautomer is at least 1:1.
 5. The method according to claim4, wherein said medium chain fatty acid triglyceride is a triglycerideof fatty acid having 6-14 carbon atoms.
 6. The method according to claim4, wherein the triglyceride is present in an amount of 1-1,000,000 partsby weight based on one part by weight of the bi-cyclic structure.
 7. Themethod according to claim 4, wherein the triglyceride is present in anamount of 5-500,000 parts by weight based on one part by weight of thebi-cyclic structure.
 8. The method according to claim 4, wherein thetriglyceride is present in an amount of 10-200,000 parts by weight basedon one part by weight of the bi-cyclic structure.
 9. The methodaccording to claim 4, wherein said triglyceride is caprylic acidtriglyceride and/or capric acid triglyceride.
 10. The method accordingto claim 4, wherein the ratio of bi-cyclic to mono-cyclic tautomer is atleast 20:1.
 11. The method according to claim 4, wherein the ratio ofbi-cyclic to mono-cyclic tautomer is about 96:4.
 12. The methodaccording to claim 1, wherein the composition is free of water.
 13. Themethod according to claim 4, wherein the composition is free of water.14. A method for treating constipation in a constipated patient orcleansing the bowel of a patient, comprising administering to saidpatient a therapeutically effective amount of a composition comprisingthe bi-cyclic and mono-cyclic tautomers of13,14-dihydro-15-keto-16,16-difluoro-prostaglandin E1, wherein the ratioof the bi-cyclic to mono-cyclic tautomer is at least 1:1.
 15. The methodaccording to claim 14, wherein the ratio of bi-cyclic to mono-cyclictautomer is at least 20:1.
 16. The method according to claim 14, whereinthe ratio of bi-cyclic to mono-cyclic tautomer is about 96:4.
 17. Themethod according to claim 14, wherein the tautomers are present in theabsence of water in the composition.
 18. A method for treatingconstipation in a constipated patient or cleansing the bowel of apatient, comprising administering to said patient a therapeuticallyeffective amount of a composition comprising the bi-cyclic andmono-cyclic tautomers of13,14-dihydro-15-keto-16,16-difluoro-prostaglandin E1, and at least onemedium fatty acid triglyceride, wherein the ratio of the bi-cyclic tomono-cyclic tautomer is at least 1:1.
 19. The method according to claim18, wherein said medium chain fatty acid triglyceride is a triglycerideof a fatty acid having 6-14 carbon atoms.
 20. The method according toclaim 18, wherein the triglyceride is present in an amount of1-1,000,000 parts by weight based on one part by weight of the bi-cyclicstructure.
 21. The method according to claim 18, wherein thetriglyceride is present in an amount of 5-500,000 parts by weight basedon one part by weight of the bi-cyclic structure.
 22. The methodaccording to claim 18, wherein the triglyceride is present in an amountof 10-200,000 parts by weight based on one part by weight of thebi-cyclic structure.
 23. The method according to claim 18, wherein saidtriglyceride is caprylic acid triglyceride and/or capric acidtriglyceride.
 24. The method according to claim 18, wherein the rationof bi-cyclic to mono-cyclic tautomer is at least 20:1.
 25. The methodaccording to claim 18, wherein the ratio of bi-cyclic to mono-cyclictautomer is about 96:4.
 26. The method according to claim 18, whereinthe tautomers are present in the absence of water in the composition.